Low temperature carbonization oven



' Sept. 26, 1933. Q HONNAY Low TEMPERATURE cARBoNIZAT-ION OVEN Filed May 9, 1951 2 Sheets-Sheet l a a 4f /40 1931 2 sheets-sheet 2 C. HONNAY Filed May 9,

LOW TEMPERATURE GARBONIZATION OVEN tented Set. 26,

This invention relates to a low temperature distillation or carbonization oven of the type in which the material fed a'heated sole is simultaneously moved forward and plougheddby the means ensuring itsv progression. Its object is to allow of continuous and economical work on a commercial scale.`

According to this invention, the coal or other material to be carbonized, is spread over the sole in an exceedingly thin layer the depth of which does not exceed l5 to 20 millimeters and it is ploughed or turned in such manner that the depth of coal remains substantially unlform throughout, i. e. so that no gaps leave the sole uncovered and no substantiel accumulations are formed above the general level of the layer of coal.

To this end, the layer of coal or other material is ploughed or turned obliquely on the sole in zigzag fashion in such manner that it is prevented from heaping ahead of the ploughing devices and is caused to close up the furrows made by the latter in their progression.

Whilst the layer of coal is thus made to progress and to be ploughed or turned without any variation in its depth, it is subjected to perfectly uniform heating by the action of a large number of heaters 'distributed at regular intervals beneath the whole surface of the sole.

Immediately upon leaving the layer of coal, the volatile products distilled therefrom are filtered by a sieve placed adjacent to and above the sole in order to separate them from the dust which may be carried away with them. The gaseous products pass through said sieve and :dll a chamber in which they impart some of their heat to a layer of coal spread upon a second sieve forming the roof of said chamber. They are then discharged, preferably under a slight vacuum, through pipesopening into the chamber comprised between the two sieves. The coal thus preheated by the gases feeds the layer undergoing distillation on the sole.

The oven for carrying out this process comprises a mume chamber within which is driven an endless conveyor of wire gauze or perforated sheet metal iitted with .transverse rows oi' obliquely placed Scrapers arranged zigzag fashion.

The lower band' oi.' the conveyor rests upon the sole of the mume ychamber and its zigzag scrapers turn or plough the thin layer of coal under distillation, whilstits upper band carries the coal to be preheated, which is fed thereto in the form of a thin layer by a suitable distributor placed at one of its ends. The. other in a joint of asbestos or other suitable material,

end of the upper band discharges the preheated coal to feed thelayer under distillation on the sole. Together with the unheated side walls of the muiie chamber, the upper and lower bands of the endless conveyor enclose the chamber into which the distillates are released after passing through the lower conveyor band which acts as a dust sieve.

The sole is uniformly heated throughout its.

surface by a plurality of rows of gas burners 85 regularly spaced and preferably arranged across it. The sole may consist of inverted U irons arranged lengthwise side by side, whose shanks are Joined together and are notched at intervals to allow the sole thus assembled freely to con- 7 tract or expand lengthwise without warping. For the same purpose, one end of the sole is supported by the rear wall of the muiiie chamber whilst the outer shanks of the two U irons at the edges of the sole rest in asbestos lined grooves. An oven according to the invention is illus Atrated by way of example in the accompanying drawings in which:

Fig. 1 is a general view of the oven in longitudinal section, Fig. 2 is a transverse section of the oven on a larger scale,

Fig. 3 shows on a larger scale a section of the endless conveyor and sole in side elevation,

Fig. 4 is a plan view of the same section of conveyor and Fig. 5 is a front view of the Scrapers.

In the upper part of the brickwork 1 of the oven shown in the drawings is enclosed a mume or distillation chamber 2 comprised between a roof 3, side walls 4, end walls 5, and a sole 6 which separates it from a heating chamber 'l extending throughout its length.

Within the muiiie or distillation chamber l2 is an endless conveyors travelling round chainwheels 9, 10 mounted on cross-shafts 11, 12 one of which is driven by motor 13 through reducing gears 1i, 15 whilst the other is drawn by two weights 16 whose function is to keep the conveyor taut. These weights 16 act upon slides 17 carrying shaft 12 in guideways 18. The frame of the endless conveyor consists of two endless chains 19 and of T iron cross members 20 which connect the chains at intervals and are attached to their carrying links by angle-pieces 20'. Panels of wire gauze stretched between the cross-members 20 are attached to the webs of the T irons and form the actual conveyor band.

Each crossmember 20 of the endless conveyor no of the gases distilled in the latter.

carries a row of thin, rectangular scrapers 22 clearly shown in Figs. 3 to 5. Fishplates 23, to which the scraper blocks 22 are fastened in groups by stems 24, grip the webs of the crossmembers 20 to which they are attached by bolts 25. All the scraper blocks 22 are arranged obliquely relatively to the crossmembers 20, those of one row pointing one way and those of the following row pointing the other way. They form a zig-zag pattern along conveyor 8 and are preferably staggered (Fig. 4).

The upper band of conveyor 8 travels on rails 26 which prevent sagging and are carried by cross 27 anchored in the side walls 4 of muiiie" of the intense ploughing to which it is subjected. veyor band rest upon the sole 6 which they scrape .f sole 6 by the burners 36 is preferably about 650 girders chamber 2. The scrapers 22 of the lower 'conthroughout its length and width.

The sole 6 consists of a plurality of inverted U irons 28 whose sides are in mutual contact and joined together by bolts or rivets 29. Triangular notches 30 are cut alternately in one and other side of each U iron in such manner as to avoid weakening the same. By this means the sole is allowed to expand or to contract under heat without buckling or warping. Provision is made for longitudinal expansion by freely resting one end of the sole loosely in a socket 3l of one end wall 5 of muiile chamber 2. This socket is stuffed with flake asbestos or other suitable material and the outside Shanks of the U irons edging the sole also bear loosely in two grooves 32 contained in the sidewalls 4 and filled with suitable stuing materials. The iixed end of the sole is anchored at the front end of the furnace in a low wall 33. A discharge hopper 34 nils the space between wall 33 and the other end wall 5 and opens into a pit 35, below the level of mue chamber 2.

The heating chamber '1, extending beneath sole 6, contains a large number of closely arranged regularly spaced cross lines of gas burners 36, fed from a main pipe 36' which is arranged outside the furnace and may be supplied with some The whole of the sole 6 whose heating surface is increased by the depending Shanks of the U irons 26, thus is very evenly heated by the small close-set gas flames of gas lines 36.

Adjoining the oven above described is a coal dryer, not shown, which may conveniently be heated by waste gases issuing from heating chamber 7. The coal or other material to be distilled leaves this dryer at a temperature of approximately 200 C. and is conveyed by suitable means 3'7 to a distributor 38 of the endlessbelt type, which feeds it to the front end of the upper band of conveyor 8 in the form of a continuous thin layer, approximately 15 to 20 millimeters in depth. The conveyor slowly carries towards the back of muiile chamber 2 the layer of coal which, as the conveyor 8 passes round the wheels 9, is transferred on to the sole 6. A curved plate 39 prevents the coal from heaping in the angle of the muille chamber.

On the sole 6 the layer of coal is ploughed and slowly propelled towards hopper 34, its depth being kept at 15 to 20 millimeters. The ploughing is effected by the Scrapers 22 of lower conveyor band 8, which simultaneously propel the coal forward and laterally in a series of alternating slants corresponding with their own oblique positions and each fragment of coal is thus made to progress along the sole in a series of zigzag courses. In addition to effectively stirring the coal and lengthening its course of travel along the sole,

height not exceeding that of the coal layer, so

as to preclude the heaping of coal ahead of them and, as no gaps are left behind them the depth of the layer remains substantially uniform in spite The temperature maintained throughout the C. so that the maximum temperature of the coal on the sole is 500 C. The temperature of the distilled gases does not exceed 450 C.

As the distilled gases are evolved from the coal under the combined'action of heat and ploughing, they escape through the wire gauze panels 2l of the lower conveyor band which retain any dust carried thereby. The filtered gases issue into space 40 enclosed between the two bands of conveyor 8 and they are discharged, preferably under a slight' vacuum, through pipes 41 opening in the side walls 4 of the muiiie chamber and led outside the furnacelto a'eollector 42. In passing through inner chamber 40, the distillation gases heat, through the wire gauze of conveyor 8, the layer of' coal spread upon the upper band of the same and 'raise its temperature lto 300 C.' ap proximately, a substantial part of their heat thus being recuperated.'4

Decomposition of the tar is precluded owingto the fact that the gases are evacuated so soon as they are freed,l and it has been found that the phenol content of the tar obtained by this process does not exceed 25%. Owing also to the ltering of the gases through the gauze conveyor, the percentage of coal dust in the tar does not exceed 1/2 whereas it has reached as much as 30% in some of the ovens proposedheretofore.

The semi coke resulting from the carbonization drops from the end of the sole' 6 into hopper 34 and thence into a watertight pit 35, where the remaining tar imparts thereto the consistency of a paste which may then be immediately pressed into agglomerates, without the use of binding materials. It may also be discharged, without treatment, by any suitable means. i

A distillation oven as above described may be started in a few hours and remain in continuous service for several. months without being extinguished for repairs orcleaning. Its normal hourly output is about 100 kilos of semi-coke per square meter of heated surface. z

It will be understood that the invention is not restricted to the constructional details herein de-l scribed and illustrated by way of example in the accompanying drawings and that the construction may be varied without departing from the scope of this invention as set forth in the appendedclainis. vr Iclaim: l,

1. In a low temperature distilling and carbonizing oven, the combination with a chamber, of an endless band sievel mounted for rotation around horizontal axes in said chamber; said sieve comprising an upper portion and a lower portion substantially parallel tol each other, means for moving said sieve, rows of Scrapers arranged exteriorly on said portions obliquely to the direcamasar tion of movement of said sieve, means for feeding material to be treatedto said upper portion, a. sole in the chambr under said sieve adapted to receive material discharged from the sieve, said scrapers being adapted to plough the material on said sole, means for subjecting the sole to substantially uniform temperature throughout its area, and a gas oil'take pipe communicating with said chamber between the upper and lower portions of said sieve. n

' 2. In a low temperature distilling and carbonizing oven, the combination with a chamber having side walls and a sole, of an endless band sieve mounted for rotation around horizontal axes in said chamber, said sieve comprising two superposed parallel portions being adapted to lter gas distilled from material on said sole, rows of obliquely arranged Scrapers secured exteriorly to said sieve, a gas oitake pipe opening above the lower portion and below the upper portion of said sieve, means for feeding material to be treated on said upper portion and thence to lsaid sole, means for uniformly heating said sole over its entire surface, one end of said sole being anchored to one wall of said chamber only.

3. In a low temperature distilling and carbonizing oven, the combination with a` chamber having side walls and a sole, of an endless band conveyor in said chamber having upper and lower superposed horizontal portions, said conveyor portions each having a foraminous endless carrying surface, a pair of endless chains adjacent the edges of vsaid carrying surface, and transverse members secured to said chains; rows of scrapers secured to each of said transverse members, said Scrapers projecting away from the said carrying surface and comprising each a shallow body portion arranged at an acute angle to the Vdirection of travel of said conveyor and each scraper having a stem portion secured to one of said transverse members, means for moving said conveyor, means for discharging material to be treated onto said upper portion, said conveyor being adapted to discharge material onto said sole, said Scrapers being arranged to plough over said sole when passing thereover, and oftake means for evacuating gas from the space in the chamber between said two portions of the conveyor.

CHARLES HONNY.

iso 

